Preparation of amphoteric surface active agents

ABSTRACT

R IS HYDROGEN OR AS ALKYL HAVING 1 TO 4 CARBON ATOMS, AND N IS THE INTEGER 1 OR 2, OR (B) A MIXTURE OF SAID SOLVENT AND AN ADDITIONAL SOLVENT SELECTED FROM THE GROUP CONSISTING OF METHANOL, ETHANOL, PROPANOL OR DIOXANE, WITH THE AMOUNT OF SAID ADDITIONAL SOLVENT NOT EXCEEDING 80% BY WEIGHT OF THE TOTAL WEIGHT OF THE SOLVENT USED.   WHEREIN:   RO(CH2CH2O)2H   A METHOD FOR PREPARING BETAINE TYPE AMPHOTERIC SURFACE ACTIVE AGENTS BY REACTING A TERTIARY AMINE CONTAINING POLYOXYETHYLENE RADICALS AND AN ALKALI METAL SALT OR AN AMMONIUM SALT OF MONOCHLOROACETIC ACID IN EITHER (A) A SOLVENT HAVING THE FORMULA

United States Patent- Office 3,555,079 Patented Jan. 12, 1971 3,555,079- r-PR B RATIQN OF AMPHOTERIC SURFACE.-

ACTIVE AGENTS. Hitleo Marumo, Tokyo, and Minru Saitoh, Saitama-ken, Japan,assigngrg'toLion llat '& ,Oil Co., Ltd., Tokyo, QZJ P aJaJw pD o p'ahf ""No'Drawingk'continuationof application Ser. No.

593,688, Nov. 14,1966. This application Aug. 18, 1969, Ser. No. 853*,594 Int. C l. '(';207c -1 '01 /00 us or. zen-501.13 9 Claims 1 ABSTRACT OF 'THEDISCLOSURE A method for pr eparingbetaine type amphoteric surface active agents by reacting a tertiary amine containing polyoxyethylene radicals and an alkali metal salt or an ammonium salt of monochloroacetic acid in either (a) a solvent having the formula R0(CH CH O) H wherein:

This application is a continuation of application Ser. No. 593,688 filed Nov. 14, 1966, and now abandoned.

The present invention relates to an improvement in methods for synthesizing betaine type amphoteric surface active agents by a reaction between a tertiary amine and a monochloroacetate, and more particularly to a method for synthesizing betaine type amphoteric surfactants by means of a reaction between a tertiary amine having polyoxyethylene radicals and an alkali metal salt or an ammonium salt of monochloroacetic acid in (a) a solvent of the following Formula 1 or (b) in a water-soluble organic solvent containing at least 20% by weight of a solvent of said Formula 1, namely,

RO(CH CH O) H 1 wherein:

R represents an alkyl radical having 1 to 4 carbon atoms,

or hydrogen. n represents an integer 1 or 2.

In the amphoteric surface active agent industry, it has been the general practice that the preparation of betaine type amphoteric surface active agents by amphoterizing amines has utilized a reaction between an amine and an aqueous solution of monochloroacetate. More specifically, the prior methods of synthesizing such amphoteric surface active agents comprise the steps of first dissolving or emulsifying an amine in water, subsequently adding thereto an aqueous solution of sodium monochloroacetate, and heating the mixture at a temperature in the range from 90 C. to 100 C. in the presence of sodium hydroxide to a reaction therebetween. Sodium hydroxide serves to seize the chlorine which is isolated during the course of reaction. The prior methods are satisfactory effecting amphoterization of alkylimidazoline and a satisfactory amphoteric surface active agent is obtained. However, such prior method works very poorly in the amphoterization of polyoxyethylene alkylamine. The fact that the amphoterizing reaction does not proceed satisfactorily, in spite of the intensive solubility of the sodium monochloroacetate in water, may be attributed to the poor solubility of the polyoxyethylene alkylamine in a strong, alkaline aqueous solution and also to the fact that in said aqueous solution the product accruing from the reaction between the polyoxyethylene alkylamine and the salt of monochloroacetic acid decomposes into an amine and a salt of glycol acid. In fact, it has been observed by the inventors that in such an instance the reaction product shows a tendency to decompose in said aqueous solution to produce an amine. For this reason, the prior amphoterizing processes are not suitable when amines having polyoxyethylene radicals are used as the starting materials. Moreover, the prior amphoterizing processes perform reactions in an aqueous solution as has been described, and as an inevitable consequence, the amphoteric surface active agents which are the final products thus obtained always contained water. For this reason, the separation of the amphoteric surface active agents from the water was accompanied by severe formation of bubbles which, in turn, constituted a serious cause for the difiiculty in the separation of effecting water from the surface active agent.

The present invention contemplates providing an improved method for the amphoterization of a tertiary amine having polyoxyethylene radicals, which in practice has been quite difiicult using the prior methods. The improved method makes it possible to achieve a smooth progress of the amphoterizing reaction and also easy separation of the solvent from the reaction product as a result of the use of a specific solvent in the reaction.

The amphoterizing reaction performed on tertiary amines, in the present invention, is conducted basically by placing a tertiary amine having polyoxyethylene radicals in contact with an alkaline salt of monochloroacetic acid in a solvent, as will be described hereinafter, and also in the presence of alkali which is intended to seize the chlorine formed during the reaction. According to the present invention there is no particular restriction on the order of the feeding of the materials, such as the amine or amine solution, the monochloroacetate slurry and the alkaline solution. In practice, however, it is preferred to appropriately select the feeding order depending on the nature (chiefly the melting point) of the amine used, in order to obtain a desirable result. Such order of feeding will be made clear in the examples which will be given later.

The solvent which is used in the method of the present invention for the synthesis of amphoteric surface active agents is as indicated by the aforedescribed Formula 1. This group of solvents includes ethylene glycol, diethylene glycol, an ethylene glycol monoalkyl ether such as ethylene glycol monomethyl ether, ethylene glycol monoethylether, ethylene glycol monopropyl ether and ethylene glycol monobutyl ether, and also includes a diethylene glycol monoalkyl ether such as diethylene glycol monomethyl ether, diethylene glycol monoethyl ether, diethylene glycol monopropyl ether and diethylene glycol monobutyl ether.

One or more water-soluble organic solvents selected from the group consisting of methanol, ethanol, propanol or dioxane may be used in combination with the aforesaid solvent indicated by the Formula 1, but the amount of such additional organic solvents must not exceed by weight of the total weight of the organic solvent used.

The term alkaline salt of monochloroacetic acid as used herein, refers to and includes the sodium, potassium, lithium or ammonium salts respectively, of monochloroacetic acid. These alkaline salts of monochloroacetic acid are prepared by first dissolving monochloroacetic acid in said solvent and then adding an aqueous solution of sodium hydroxide, an aqueous solution of potassium hydroxide, an aqueous solution of lithium hydroxide or ammonia water, while holding said solution at a temperature of 50 C. or less. If an excess of alkali is used during the step of preparing said alkaline salt of monochloroacetic acid, there is no need of adding alkali for the purpose of seizing the chlorine produced in the amphoterizing reaction. Because the alkaline salts of monochloroacetic acid are of a poor solubility, it is customary that these salts are obtained in slurry form, but this state of the salts does not in any way adversely affect the amphoterizing reaction. While amphoterizing reactions are performed, in general, at a temperature in the range of from 50 C. to 200 C. for a length of time ranging from 0.5 to 5 hours, it is desirable from the viewpoint of performing an efficient reaction to make an appropriate selection of the conditions of the reaction so as to suit the type of the amines used. It is known that the velocity of amphoterizing reactions increases with an increase in the concentration of the reacting solution. However, the preferred degree of concentration of such reacting solution is usually 50% by weight.

The amines which can be used in the present invention as the starting materials include all of the tertiary amines having a polyoxyethylene radical. However, these tertiary amines may be divided into three types. The amphoterizing reactions for each type of amine are as follows:

HzCOOA wherein: p+q=2 to 50 (CllzClI2O) lI R-NCH2CH2CH2N (CH2CHzO) II (CIIzClIsOJJI wherein: 1:1 to 50 O l crncoox -+R cmoutcugr r l (oincuzomr i/ CHzClLOMlI 2.\Cl

wherein: p+q+r=3 to 50 Where an excessive amount of a salt of monochloroacetic acid is used, there may occur a reaction between the hydroxyl radical located in the terminal of the polyoxyethylene radical and the salt of monochloroacetic acid, resulting in the polyoxyethylene radical being converted to one of the group of (CH CH O) CH COOA. However, it is to be noted that the present invention includes such phenomenon.

While it is one of the noteworthy features of the present invention to use a solvent as is indicated in the aforesaid Formula 1 as the solvent for the amphoterizing reaction, this solvent is presumed to have a specific ability as far as amphoteric reactions are concerned. For example, when a water-soluble methanol, ethanol, propanol or dioxane is used as the only reaction solvent in the same manner as described for the use of the solvent of the present invention, there is obtained no satisfactory progress in the amphoterizing reaction. This is considered to be due to the fact that the solubility of the salt of the monochloroacetic acid in the water-soluble solvent indicated by the Formula 1 is markedly greater than it is .in other water-soluble solvents.

According to the present invention, not only the amphoterization of polyoxyethylene alkylamines by a salt of monochloroacetic acid can be carried out with a satisfactory efficiericy and in a relatively short periodof time, but also the reaction products are easily separated from the solvent. When a considerable amount of water is present in the solvent used in the reaction, the water is boiled together with the co-present ethylene glycol monoalkyl ether, diethylene glycol monoalkyl ether or the like, and as a consequence, it can be easily removed almost without developing any bubbling.

EXAMPLE 1 To 104 gr. of monochloroacetic acid packed in a reaction vessel were added 426 gr. of a mixed solvent of ethylene glycol monomethyl ether and methanol (the ratio by weight being 4:6), thereby dissolving the former in said solvent. The resulting solution was neutralized by the addition thereto of 88 gr. of aqueous solution of a 50% sodium hydroxide, While holding the solution at a (CHzCHzOklH temperature of 50 C. or less. Into this mixture were introduced 88 gr. of aqueous solution of a 50% sodium hydroxide and also 362 gr. of polyoxyethylene laurylamine (the mean additional mol number of ethylene oxide being 4), then allowing the mixture to react at a temperature between C. and 90 C. for 2 hours while being stirred.

After filtering the reacted solution and after removing the by-product thereon, the precipitate was washed with isopropanol. The filtered sodium chloride liquid and the washing liquid were mixed together. After removing the solvent by distillation under a reduced pressure, the residue was mixed with benzene to dissolve the residue therein. The resulting solution was filtered to completely remove the sodium chloride, a by-product. The filtered liquid was distilled under a reduced pressure to remove benzene therefrom, and thus 459 gr. of reaction product Were obtained.

The rate of reaction was determined on the reaction product by measuring the total base content (the sum of nitrogen and sodium) of the reaction product by the potentiometric titration using hydrochloric acid, and by measuring the nitrogen content by Kjeldahl method, as follow:

Total base content-4.33 l0 eqv./gr. Nitrogen content2.96% Reaction rati0105.2% Yield-99.8%

EXAMPLE 2 To a tertiary amine containing polyoxyethylene radicals packed in a reaction vessel was added an organic solvent, thereby dissolving the amine in the solvent. Separately therefrom, monochloroacetic acid was dissolved in an or ganic solvent, and while holding the resulting solution at a temperature of 50 C. or less, said solution was neutralized by the use of a 50% aqueous solution of caustic alkali. The neutralized solution was added to said amine solution. This was added to a 50% aqueous solution of caustic alkali and the mixture was heated to cause a reaction. I

By;-treating the reacted solution in the same manner as in Example 1, a reaction product was obtained. The rate of the reaction was determined by the same analytical pr c du e 7 The type and the amount of the amine, the organic solventand the caustic alkali usedv are shown in Table 1, while the reaction conditions and the analysis of the retralize this solution while holding the latter at a temperature of 50 C. or less. Into this solution was introduced a solution of a tertiary amine containing polyoxyethylene radical in an organic solvent and also a 50% aqueous solution of caustic alkali, and the mixture was heated to efiect a reaction while being stirred. The reacted solution was then treated in the same manner as in Example 1 and a reaction product was obtained. The

action product andthe ;yie ldare shown in Table 2.

TABLE 1 Amine solution Alkaline salt of monochloroacetic acid Mono- Caustic chloroalkali 50% Caustic 'A'mine' acetic aqueous alkali 50% acid, solution, aqueous solu- Number Type R p+q+r Grams Solvent, grams grams Solvent, grams grams tion, grams 1 I CmHa-l 2 400 Ethyleneglycolmono- 116 Ethyleneglycolmono- NaOH 98 NaOH 9g methylether, 209 methylether, 263 2 I CmHzw 50 618 Ethyleneglycolmono- 26 Ethyleneglycolmono- NaOH 22 NaOH 22 butylether, 585 butylether, 59

Ethyleneglycolmono- Ethyleneglycolmono- 3 I 0131135 708 methylether, 215 104 methylether, 94 methyl NaOH 38 NaOH 88 Methyl alcohol, 322 Alcohol, 141 Ethyleneglycolmono- Ethyleneglycolmono- 4 II 0151131 296 ethylether, 74 26 ethylether, Isopropyl KOH 31 KOH 31 l H W n I v Isopropyl alcohol, 173 lcohol, 5 I1 C H 30 553 Diethyleneglycolmono- 42 Diethyleneglycohnono- NaOH 36 NaOH 36 ethylether, 483 ethylether, 96 6 III 61 115 15 987 Methyl alcohol, 670 209 Ethyleneglycolmono- NaOH 176 NaOH 176 v butylether, 446 f" f. Diethyleneglycolmono- Diethyleneglycolmono- KOH 62 KOH 62 7 I11 CmH'm. 30 412 methylether, 48 52 methylether, 130

' Isopropyl alcohol, 266

-- 'f' 1 TABLE 2 Product Reaction Total base Temperacontent Reaction Yield ture Time, X10 eq. N content ratio, C.) ghours v./g." percent percent grams percent at of the reaction wa determined b h sam anal tical EXAMPLE 3 r e S e 6 Y procedure as used in Example 1.

The type and the amount of the amine, the organic solvent and the caustic alkali are shown in Table 3, while 45 the reaction conditions, the analysis of the reaction product and the yield are shown in Table 4.

Into the monochloro acetic acid'packed in a reaction vessel was introduced an organic solvent, thereby dissolving the said acid. The resulting solution was mixed with a 50% aqueous solution of caustic alkali to neu- TABLE 3 Amine solution Alkaline salt of monochloroacetic acid Mono Caustic Caustic chloroalkali 50% alkali 50% Almne acetic acqueous aqueous acid, solution, solution, B. p+q+r grams Solvent, grams grams Solvent, grams grams grams Ethyleneglycol-82 Ethyleneglycol-50 012E 10 397 Monoethylether, 82 66 monoethylether, 50 KOH, 79 KOH, 70

Methyl alcohol, 191 Methyl alcohol, C H 4 446 Ethyleneglycol- 104 Isopropyl alcohol 255 NaOH, 88 NaOH, 88

. monobutylether, 255 0 11 30 398 'DiethyleneglycoL 26 Diethyleneglycol- NaOH, 22 NaOH 22k monomethylether, 355 monomethylether, 59 t Ethyleneglycol- (1 11 2 356 1,4-dioxane, 185 104 monoethylether, 84 N aOH, 88 NaOH, 88

' Y 1,4-dioxane, 151 0 11125 10 397 Ethyl alcohol, 301 52 Diethyleneglycol- NaOH, 44 NaOH, 44 q Eth 1 1 1 monoethylether, H yenegyco,8 3151 13; 20 v 175,{Isopr0py1a1c0h0l, I 13 Ethyleneglycol, 29 NaOH, 11 NaOH 11 TABLE 4 Product Reaction -T0tal base Reaction Yield Tempera- Time, content N content ratio, ture, 0. hour X10oeqv./g. percent percent Grams Percent 7 EXAMPLE 4 Into the monochloroacetic acid packed in a reaction vessel was introduced an organic solvent, thereby dissolving the former. While holding the resulting solution at ethylene laurylamine and about 2 mols of potassium monochloro acetate.

The embodiments of the invention in which an exclusive property or privilege is claimed are defined as follows:

a temperature of 50 C. or less, the solution was neutral- 5 1 A th d f b t t h t ized by the addition of a 50% aqueous solution of caustic or fi g T ame P 0 enc alkali. The resulting mixture was mixed with a tertiary Sur if; ac f l 1C z g amine containing polyoxyethylene radicals and also with er E ammed Se ec e 21 l a 50% aqueous solution of 50% caustic alkali, and the 5 mg i represlen e y e o owmg mixture was heated to effect a reaction while being stirred. 0mm as rough name y treating the reacted solution in the same manner R N (CHZCHZO)PH as in Example 1, a reactlon product was obtamed. The rate of the reaction was determined by the same ana- (CHiCHZmqH (I) lytical procedure as used in Example 1.

wherein. -2 to 50 The type and the amount of the amine, the organlc p+q solvent and the caustic alkali used in the reaction are shown in Table 5, while the conditions of the reaction, N(CHzCHzO)pH (11) the analysis of the product and the yield are shown in Table 6.

TABLE 5 Amine Alkaline salt of monochloroacetic acid Monochloro- Caustic alkali Caustic alkali acetic 50% aqueous 50% aqueous acid, solution, solution, Number Type R p+q+r Grams grams Solvent, grams grams grams Ethyleneglycol-monomethyl- 14 1 0121125 2 274 104 ether, 101 NaOH, 88 NaOH, 88

Isopropyl alcohol, 237 15 I 015113 10 355 52 Ethyleneglycol- NaOH, 44 NaOH, 44

monoethylether, 387 16 1 Tallow 8 201 Etllylenggzlgyeol-monomethyl- NaOH, 30 NaOH, 30

e r, Ethyleneglycol-monomethyl- 17 III 0111125 3 375 19s ether, 100 NaOH,168 NaOH, 168

1,4-dioxane, 397 18 III o r! 15 452 104 Ethyleneglycol, 516 KOH 123 KOH 123 TABLE 5 Product Reaction Total base content, Reaction Yield Tempera- Time, X104 cqv./ N content, ratio, No ture, 0. hours g. percent percent Grams Percent 14 80-85 3 5.28 3.01 104.7 358 98.7 1 2. 39 1. 55 102. 5 400 09. o 1 2. 79 1. 91 105. 1 233 99. 7 3 6. 95 4. 99 95. 2 555 97. 2 3 a. 52 2. 49 97. s 549 91. 0

EXAMPLE 5 wherein: p=1 to To 208 gr. (2.2 mols) of monochloroacetic acid packed /(CH2CHzO)qH in a reaction vessel were added 755 gr. of a mixed solvent (111) of ethylene glycol monomethyl ether and 1,4dioxane (the ratio by weight being 1:1), thereby dissolving the former (CHZCHZONH (CHZCHZOfiH in said solvent. The resulting solution was neutralized by the addition thereto of 246 gr. (2.2 mols) of aqueous wherein: p+q-|-r=3 to 50 solution of a 50% potassium hydroxide, while holding wherein: the solution at a temperature of 50 C. or less. Into R is an alkyl radical having 6 to 22 carbon atoms, this mixture were introduced 626 gr. (1.0 mol) of poly- R is an alkyl radical having 6 to 22 carbon atoms, oxyethylene laurylamine (the mean additional mol numwith her of the ethylene oxide being 10) and also 246 gr. of (B) an alkaline salt selected from the group consisting aqueous solution of a 50% potassium hydroxide, then of the sodium, potassium, lithium and ammonium the mixture was allowed to react at a temperature besalts of monochloroacetic acid, tween 95 C. and 100 C. for 4 hours. 5 (C) in the presence of alkali, the amount of said alkali The reacted solution was then treated in the same being approximately equivalent, on a molar basis, to manner as Example 1, and 811 gr. of reaction product the amount of said alkaline salt, and were obtained. In the same analytical procedure, the rate (D) in a solution containing a minor amount of water of reaction was determined, with the following result: and the balance of the solution being a solvent selected from the group consisting of (a) solvents T( )ta1basecontent344xm a eqvJ-gr' represented by the following Formula IV and (b) Nftrogen Cntent 1' 3% mixtures containing at least 20 percent by weight of the solvent represented by said Formula IV and From this result of analysis, it is noted that the reaction the balance of said mixture being a water-soluble product is a result of reaction between 1 mol of polyoxyorganic solvent selected from the group consisting of methanol, ethanol, propanol, dioxane and mixtures thereof,

R"O(CH CH O),,H (IV) wherein:

R" is selected from the group consisting of alkyl radicals having 1 to 4 carbon atoms and hydrogen,

n is the integer 1 or 2.

2. A method for preparing betaine type amphoteric surface active agents according to claim 1, wherein the solvent used in the reaction is selected from the group consisting of ethylene glycol and ethylene glycol monoalkyl ether in which the alkyl radical has 1 to 4 carbon atoms.

3. A method for preparing betaine type amphoteric surface active agents according to claim 1, wherein the solvent used in the reaction is selected from the group consisting of diethylene glycol and diethylene glycol monoalkyl ether in which the alkyl radical has 1 to 4 carbon atoms.

4. A method for preparing betaine type amphoteric surface active agents according to claim 1, wherein the solvent used in the reaction consists of a mixture containing 20 percent or more by weight of a member selected from the group consisting of ethylene glycol and ethylene glycol monoalkyl ether in which the alkyl radical has 1 to 4 carbon atoms, and the balance consisting of one or more members selected from the group consisting of methanol, ethanol, propanol and dioxane.

5. A method for preparing betaine type amphoteric surface active agents according to claim 1, wherein the solvent used in the reaction consists of a mixture containing 20 percent or more by weight of a member selected from the group consisting of diethylene glycol and diethylene glycol monoalkyl ether in which the alkyl radical has 1 to 4' carbon atoms and the balance consisting of one or 1 0 more members selected from the group consisting of methanol, ethanol, propanol and dioxane'.

6. A method for preparing betaine type amphoteric surface active agents according to claim 2, wherein the alkali is selected from the group consisting of aqueous solutions of sodium hydroxide, potassium hydroxide, lithium hydroxide and ammonia.

7. A method for preparing betaine type amphoteric surface active agents according to claim 3, wherein the alkali is selected from the group consisting of aqueous solutions of sodium hydroxide, potassium hydroxide, lithium hydroxide and ammonia.

8. A method for preparing betaine type amphoteric surface active agents according to claim 4, wherein the alkali is selected from the group consisting of aqueous solutions of sodium hydroxide, potassium hydroxide, lithium hydroxide and ammonia.

9. A method for preparing betaine type amphoteric surface active agents according to claim 5, wherein the alkali is selected from the group consisting of aqueous solutions of sodium hydroxide, potassium hydroxide, lithium hydroxide and ammonia.

References Cited UNITED STATES PATENTS 2,129,264 9/1938 Dowining et al. 260l.l3

2,082,275 6/ 1937 Daimler et al 260-50113 FOREIGN PATENTS 373,555 1962 Japan 260-50113 OTHER REFERENCES Scheflan et al.: The Handbook of Solvents, Van Nostrand & Co. Inc., N.Y., p. (1953).

r BERNARD H-ELFIN, Primary Examiner M. W. GLYNN, Assistant Examiner 

